ruby-****@sourc*****
ruby-****@sourc*****
2004年 4月 3日 (土) 07:28:54 JST
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REMOTE_ADDR = 200.216.151.125
REMOTE_HOST =
URL = http://ruby-gnome2.sourceforge.jp/en/?tut-gtk2-packing-box-details
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- {{link "tut-gtk2-packing-theory", "tut-gtk2-packing-intro", "tut-gtk", "tut-gtk2-packing-demo"}}
= Details of Boxes
+ {{link "tut-gtk2-packing-theory", "tut-gtk2-packing-intro", "tut-gtk", "tut-gtk2-packing-demo"}}
Because of this flexibility, packing boxes in GTK can be confusing at first. There are a lot of options, and it's
not immediately obvious how they all fit together. In the end, however, there are basically five different styles.
{{image_left("packbox1.png")}}{{br}}
Each line contains one horizontal box (hbox) with several buttons. The call of Gtk::Box#pack is shorthand for the
call to pack each of the buttons into the hbox. Each of the buttons is packed into the hbox the same way (i.e.,
same arguments to the Gtk::Box#pack_start method).
The Gtk::Box#pack_start method looks like this:
Gtk::Box#pack_start(child, expand, fill, padding)
The first argument is the object you are packing the into the box. The objects will all be buttons for now, so
we'll be packing buttons into boxes.
The expand argument to Gtk::Box#pack_start and Gtk::Box#pack_end controls whether the widgets are laid out in
the box:
:If expand is true
widgets will fill in all the extra space in the box so the box is automatically expanded to fill the area
allotted to it;
:If expand is false
the box is shrunk to just fit the widgets.
By setting expand to false will allow you to do right and left justification of your widgets. Otherwise, they will
all expand to fit into the box, and the same effect could be achieved by using only one of Gtk::Box#pack_start or Gtk::Box#pack_end.
The fill argument controls where the space given to the object by the expand option is allocated:
:If fill is true
the object is extented to fit the allocated space;
:If fill is false
the object is left with its original size, and extra padding is added around it.
Note that the fill argument only has an effect if the expand argument is also true.
When creating a new horizontal box, it looks like this:
Gtk::HBox.new(homogeneous, spacing)
The homogeneous argument to Gtk::HBox.new (and the same for Gtk::VBox.new) controls whether each object in the box has the same size (i.e., the same width in an hbox, or the same height in a vbox). If it is set, the Gtk::Box#pack_start or Gtk::Box#pack_end methods work essentially as if the expand argument was always set to true.
What's the difference between spacing (set when the box is created) and padding (set when elements are packed)?
Spacing is added between objects, and padding is added on either side of an object. The following screenshot should
make it clearer:
{{image_left("packbox2.png")}}{{br}}
Following is the code used to create the above screenshots. It is commented fairly heavily so I hope you won't have
any problems following it. Just play with it.